Epigenetic changes in transcribed regions of the genes, such as DNA methylation, covalent modifications of histones, and ATP-dependent chromatin remodeling, have been recently identified as key universal components that regulate gene expression. Among these epigenetic modificators are large protein ensembles RSC, Swi/Snf, iSwi and histone modification factors that increase accessibility of chromatin to transcription. RNA polymerase itself and the associated transcription elongation factors may also work to establish and maintain the active state of the chromatin.The major results: 1. The yeast chromatin-remodeling complex RSC reduces nucleosomal barrier to Pol II in vitro. The mechanism of the reduction is currently being investigated.2. The yeast transcript cleavage factor TFIIS facilitates transcription through nucleosomes by Pol II. RSC and TFIIS cooperate in the process.3. We determine the fate of nucleosomes after factor-stimulated transcription by Pol II.